Coupling agents are known in polymer materials and are useful for creating interactions between the polymer material and a surface of a particulate solid (typically an inorganic filler particle). Common coupling agents include organosilanes, or dispersants containing a carboxylic acid. The coupling agent is believed to form interactions with the particulate solid by bonds forming between the coupling agent and the particulate solid.
A coupling agent containing a carboxylic acid are described in articles including A. Tabtiang et al., Composite Interfaces, 6, 65 (1999); C. M. Liauw et al., Plastics, Rubber and Composites Processing and Applications, 24, 211, (1995); and C. M. Liauw et al., J. Adhesion Sci. and Tech., 15, 889, (2001). All three references disclose maleic anhydride copolymers that open the anhydride ring and the carboxylic acid groups then bond directly with the particulate solid. The coupling agent containing a carboxylic acid typically is required to be utilised in large amounts. Large amounts of the coupling agent, typically lead to detrimental performance including modified degradation of the plastic material and/or side reactions resulting in compatibility problems between the plastic material and the coupling agent.
U.S. Pat. No. 4,722,947 discloses film-forming radiation-curable low molecular weight partial ester copolymer compositions of a terminally ethylenically unsaturated compound and maleic anhydride characterised by having free-anhydride functionality. The copolymer is produced by esterifying a hydroxyalkyl acrylyl compound with a monohydric alcohol.
U.S. Pat. No. 4,533,723 discloses semi-esters of polyisobutylene succinic acid. The semi-esters are prepared from hydroxyalkyl(meth)acrylates.
U.S. Pat. No. 5,665,828 discloses a polybutylene polymer or oligomer which contains in its molecule at least one acryl group, the polybutylene polymer is prepared by reacting an anhydride-functional polybutylene polymer or derivative thereof with an acryl-functional compound having at least one hydroxyl-containing group, chlorine, isocyanate group, epoxy group or an amine group.
International Application WO 04/092227 discloses polyisobutenyl(meth)acrylates useful in photocurable lacquers and adhesives.
Organosilane coupling agents are typically formed by complex processes and many additionally are less effective in interacting with a wide range of particulate solids.
Hence, there is a need for a coupling agent capable of overcoming problems associated with the art.